The present invention relates to a multicolor sublimation type thermal recording method for making a hard copy of a color image and a device therefor.
A method of making a hard copy of a color image is generally classified into the ink jet system and the thermal transfer system. The thermal transfer system includes the system of effecting thermal recording using a sublimation type thermosensitive transfer paper and the system of effecting thermal recording using a wax type thermosensitive transfer paper. Among these systems, the system using a sublimation type thermosensitive transfer paper can obtain a clear or distinct image as compared with other systems. Accordingly, it can be said that such to sublimation type thermal recording system is most suitable for making a high quality color hard copy.
On the other hand, for color image to be applied as the hard copy, there are various pictorial images e.g. a video image, a computer graphic image, a pictorial image, a photographic image and a print image, etc. It is possible to make hard copies of these various pictorial images on the basis of the system using the abovementioned sublimation type thermosensitive transfer paper. Such a hard copy is made as follows. First is to make data indicative of three primary colors (which will be simply referred to as "three primary color data" hereinafter) of the above-mentioned various pictorial images to input this three original color data to a sublimation transfer printer in which the above-said sublimation type thermosensitive transfer paper is used. The sublimation transfer printer drives a thermal head on the basis of the input pictorial image data to sublimation-transfer dye contained in a transfer layer of a sublimation transfer sheet onto an image-receiving paper per each color, thus to form a color image on the image-receiving paper.
Method for inputting the three primary color data of the various pictorial images to the sublimation transfer printer is easily carried out, although they are different depending upon the kind of pictorial images. Namely, in the case of a computer graphic image, since the image is formed with three primary color data comprising R (red), G (green) and B (blue), it is possible to employ a method of directly inputting the three primary color data of R, G and B to the sublimation transfer printer. In the case of a video image, it is possible to employ a method to convert video signals forming the image into three primary color data of R, G and B or Y (yellow), M (magenta) and C (cyan) to input the three primary data to the sublimation transfer printer. Further, in the case of a pictorial image, a photographic image, or a print image, etc., it is possible to employ a method to read an image using a television camera or a scanner, etc. to input the image data thus read to the sublimation transfer printer directly or after conversion processing is applied to the image data to convert it into the three primary color data.
However, as stated above, when there is employed the method to input the three primary color data of various pictorial images to the sublimation transfer printer- to simply drive a thermal head in accordance with the input data, only a poor quality image considerably different from an actual image can be obtained, thus failing to make a high precision and high quality color hard copy.